of the Hampshire Tertiary District. 
127 
In the district which I have examined there is not a sufficient 
extent of the Barton clays and Bracklesham sands of the Middle 
Bagfshots uncovered by superficial deposits to demand any notice 
of their agricultural characters. 
The Lower Eocenes (London and plastic beds) are distin- 
guishable by the most cursory observation as forming a zone of 
cultivated and wooded country, which borders the Middle Eocenes, 
and contrasts strongly with their dreary wastes. This superior 
fertility arises from a different arrangement of their argillaceous 
and arenaceous constituents. The sand and clay, instead of 
being in separate beds, are more intimately mixed, and the 
sands are of finer grain. They consist, in the upper or London 
clay portion, for the most part of fine sands, clayey sands, and 
sandy clays, or brick-earth, passing downwards into strong clay 
resting upon sand, and frequently containing bands of argil- 
laceous iron-stone. Tlie beds of clay, particularly where iron- 
stone abounds, yield, when exposed on the surface, soils anything 
but fertile. The Lower Eocenes also contain, locally, beds of 
coarse siliceous sand and sandstone, which afford soils as sterile 
as any portion of the Middle Eocenes or Bagshot series. 
The base of the whole tertiary series is the plastic or mottled 
clay, in which red, yellow, and plum-colour are the prevailing 
hues. It seldom exposes a wide surface in the area under con- 
sideration. A band of sand only a foot or two thick, with large 
oyster-shells {^Ostrcea bellavocina), separates it from the chalk. 
This band lias been found, by Mr. Prestwich, to expand, in the 
tertiary district east of London, into a series, which he has 
named the Thanet sands. 
Modifications produced by the superficial Deposits. — Such is the 
general nature of the different members of the Eocene tertiaries 
of this district, and of the soils derived from them in their 
normal state : but their agricultural characters have been consi- 
derably modified by the covering of those more modern deposits 
before alluded to as having been spread over them. From the 
general absence of marine remains, the age of these superficial 
accumulations admits at present of a doubt. 
In many respects they resemble the upper erratic tertiaries 
north of the Thames ; but, as the boulder clay, or lower erratics 
— the epoch of which is defined by its superposition to the 
mammalian crag of Norfolk — does not occur in the Hampshire 
district, we cannot be certain whether the most modern tertiaries 
of the south belong to any portion of the enatic period tmtil 
they shall have been traced so far northwards as to enable their 
relations to undoubted erratic tertiaries of the pleistocene era to 
be ascertained.* They consist of beds of flint gravel, little water- 
* Six years have elapsed since this passage was written. In consequence of 
